Batteries are generally stored for various periods of time before being put into use. The batteries can be stored by the seller and frequently when purchased they are again stored by the buyer prior to being put to use. It is therefore desired to have a simple testing means for determining if a battery has sufficient charge to operate a desired device. Initially, separate battery testers were developed which could measure the strength remaining in the battery. Recently battery testers have been developed that either are included in the battery package or assembled in the label secured to the battery. The testers generally indicate the capacity remaining in the battery.
U.S. Pat. No. 4,702,564 discloses a device for testing a battery, particularly a small, portable battery, comprising a flexible, transparent substrate on which is deposited a narrow band of a black light absorbing material. A conductive material, which may taper outwardly in opposite directions from a central point to a pair of terminals, is then deposited atop the substrate on the same side of the substrate as the absorber layer or on the opposite side of the substrate as the absorber layer. A layer of a cholesteric liquid crystal material is then deposited on the substrate on the opposite side from the black absorber layer or over the absorber layer. The conductive material is an epoxy cement-based conductor, preferably silver, printed or painted directly on the substrate. An indicator scale is located along sections of the conductive material. To test a dry cell battery, the terminal ends of the conductive material are placed in contact with the battery terminals, causing a current to flow which heats the conductive material, the heat generated being the most intense at the central point and radiating outwardly. The heat is transferred through the thin substrate to the liquid crystal layer which results in a color change in the liquid crystal. The traverse of the color change along the length of the indicator scale, outwardly from the center point, is proportional to the current or voltage output or the condition of the battery to be tested and can be read on the indicator scale which is calibrated accordingly. The tester also includes means for determining the amp-hours or life of a battery.
U.S. Pat. No. 5,015,544 discloses a battery strength indicating and switch means on a battery which is coupled across the terminals of the battery and which is provided with an indicating means to indicate the strength of the battery and in addition, the battery strength indicating means is also provided with an in-line switch which can easily be depressed to complete the circuit so as to place the indicator means across the terminals of the cell and display the charge of the battery.
U.S. Pat. No. 5,059,895 discloses a battery voltmeter comprising:
(A) a dielectric layer; PA1 (B) a conductive layer above or below one of the surfaces of the dielectric layer; and PA1 (C) a temperature sensitive color indicator layer in thermal contact with the conductive layer, PA1 (i) a film base; PA1 (ii) an electrically conductive layer disposed on one side of the film base, PA1 (iii) a protective layer disposed on the electrically conductive layer, and PA1 (iv) a thermochromic layer disposed on the other side of the film base. PA1 a. Polymers polyaniline, polypyrole, polythiophene PA1 b. Binary Metal Oxides tin oxide, indium oxide, zinc oxide PA1 c. Doped Metal Oxides indium oxide doped with tin, fluorine, antimony, lead or phosphorus zinc oxide doped with aluminum or indium PA1 a. Metal Oxide Precursors PA1 a. Surfactant Doped Polyaniline, U.S. Pat. No. 5,196,144 PA1 b. Polyacid doped polyaniline, polythiophene, polypyrole and poly(p-phenylene sulfide) PA1 1. Solids content can be varied according to the viscosity desired in the ink for printing and/or the desired thickness and conductivity of the cured coating. The resistivity of a cured coating should be of the order of between 10 ohms to 5K-ohm/sq., preferably between 200-ohms/sq. and 3K-ohm/sq. for best electrochrome tester device operation. PA1 2. Conductive powder itself can be doped substoichiometric oxides such as oxide doped with Sn, F, Sb, Pb, P and mixtures thereof, Zn-oxide doped with Al and/or In, or indium-tin oxide (ITO). Some examples of the oxides are F-doped tin oxide (F--SnO.sub.2), Sb-doped tin oxide (Sb--SnO.sub.2) or Al-doped zinc oxide (Al--ZnO). PA1 3. Physical form of the conductive powder can be spherical or acicular (tree or needle like) particles or mixtures thereof. Use of the acicular particles should provide better conductivity because of the better interparticle contact; possibly a lower amount could be used to obtain the same conductivity as that with the spherical particles. PA1 4. Particle size of the conductive powder should be in a range which will provide a smooth, uniform coating, e.g., the spherical powder that could be used can be between 0.01 to 5.0 microns and preferably about 0.03 micron in diameter. PA1 5. Temperature for drying the ink is preferably 20.degree. F. but could be less than 140.degree. F. (60.degree. C.) to prevent shrinkage of a plastic substrate. A solvent or solvent mixture for the ink can be selected according to vapor pressure to provide the desired drying temperature and time. PA1 6. Suitable binders are polyester, the polyvinyl butyral (PVB) resin used by American Ink and Coatings and the polyester resin used by Acheson. The PVB binder can be used to form a composition containing, for example, 10 parts by weight acicular ITO, 40 parts spherical ITO, 3 parts PVB resin, 37.6 parts ethyl alcohol and 9.4 parts n-propyl acetate, and this composition will have a moderate drying temperature.
characterized in that the conductive layer has (1) thermal insulating means under one of its surfaces and (ii) sufficient heat generating capacity to affect a change in the temperature sensitive color indicator layer. The voltmeter can be integrated into a label and attached directly to a battery.
U.S. Pat. No. 4,835,475 discloses an apparatus for indicating the electromotive force of a dry battery which comprises:
U.S. Pat. No. 4,442,187 discloses batteries having conjugated polymer electrodes in which the conjugated polymers are doped with ionic dopant species to a preselected room temperature electrical conductivity ranging from that characteristic of semiconductor behavior to that characteristic of metallic behavior, by means of reversible electrochemical doping procedures. The electrochemical doping reactions and their reverse electrochemical undoping reactions are utilized as the charging and discharging mechanisms of lightweight secondary batteries which employ doped or dopable conjugated polymer as one or both of their electrodes.
U.S. Pat. No. 4,940,640 discloses polyaniline electrodes in which the oxidation and hydrogenation levels of the polyaniline species of the electrodes are carefully controlled. Electrochemical cells employing these electrodes function by reversible oxidation and reduction of the polyaniline species forming the electrode.
U.S. Pat. No. 5,232,631 discloses solutions and plasticized compositions of electrically conductive substituted and unsubstituted polyanilines in nonpolar organic fluid phases with functionalized protonic acids and the use of such compositions for various applications such as conductive articles.
European Patent Application 497616-A2 discloses a tester for use in determining the voltage and state-of-charge of a battery. The tester can be permanently mounted on the battery and employs an electrochromic cell which changes visual appearance, for example, color or intensity of color when electrically connected across the terminals of a battery. The electrochromic cell undergoes an oxidation/reduction reaction on direct application of the DC potential of the battery. The color of the electrochromic cell can be compared with a color comparison chart to determine the condition of the battery. The tester can be permanently electrically connected to the battery or, preferably, can be connected momentarily to determine the state of the battery.
U.S. Pat. No. 5,080,470 discloses a process for manufacturing a light modulating device employing an elementary light-modulating cell comprising a first transparent electrode, also called the working electrode; a second electrode or counter-electrode (which may be transparent or non-transparent, depending on whether the picture element is observed by direct transmission of light or by reflection); an ionic conductor or electrolytic material placed between the electrodes; means of electro-chromism; means of electrical connection to an external source of electrical voltage enabling the cell to be controlled; and means of addressing (direct, multiplexed, and so forth) enabling its selective control (present if an elementary cell is part of a multiplicity of elementary cells in one same display device). The ionic conductor or electrolyte could comprise a water soluble salt or a water-soluble mixture of salts of at least one metal which can be cathodically deposited from an aqueous solution of one of its simple or complex ions; at least one initially water-soluble film-forming polymer resin, preferably in the proportion of one part by weight to 0.05 to 50 parts of anhydrous salts; and water.
An object of the present invention is to provide a cell tester device employing a printed transparent electrically conductive electrode, such as indium-tin oxide electrode with conductive means, disposed in contact with an ionically conductive electrolyte containing at least one electrochromic material which in turn is disposed in contact with a conductive layer.
Another object of this present invention is to provide a cell tester device that utilizes, in addition to a printed indium-tin oxide electrode, a printed electrolyte containing electrochromic material and a conductive layer (counter electrode).
These and other objects will be apparent from the following description.